What color is the medical air cylinder, which contains 21% oxygen?

The correct identification of the medical air cylinder that contains 21% oxygen is indeed yellow. In the realm of medical gases, specific colors are designated to indicate the type of gas contained within cylinders; this standardization helps ensure safety and proper usage in clinical settings. The yellow cylinder identifies medical air, which is a mixture of gases including approximately 21% oxygen and 79% nitrogen. This mixture is used in various medical applications, such as providing respiratory support.

In contrast, other colors represent different gases. For example, green typically signifies oxygen, blue is often associated with nitrous oxide, and red could denote carbon dioxide in some regions. Understanding these color codes is crucial for healthcare providers to prevent errors during emergency and routine care situations.